16 



MASS. EXPERIMENT STATION BULLETIN 353 



Eastern Tent Caterpillar 



Malacosoma americana F. 



This insect is a native of North America where it is known to have been a 

 pest since 1646. It feeds upon the foliage of several trees and shrubs and, when 

 abundant, may cause complete defoliation. Except in severe cases, however, 

 caterpillars themselves and their unsightly gray nests are even more annoying 

 than the actual damage done. The favorite hosts are black cherry, fire cherry, 

 and chokecherry. Next to these, apple is undoubtedly most preferred. 



Description. The adult female measures about 13^ inches across the expanded 

 wings; the male about 1 1/8 inches. Both are reddish-brown with two oblique 

 whitish stripes on each front wing. 



The eggs are grayish in color, about 1/8 inch long, and laid on end in clusters 

 of about 350. The cluster, which commonly encircles a small twig but sometimes 

 only partly surrounds it, is covered with a protective coating, brown to black in 

 color, which when newly deposited gives the cluster a varnished appearance. 



Eastern Tent Caterpillars on Their Characteristic Tent. 



Photo by Robert L. Coffin. 



